Resistive RAM is a promising nonvolatile memory. In particular, WOx RRAM has promising memory characteristics, as discussed in M. J Lee, “2-stack ID-IR Cross-point Structure with Oxide Diodes as Switch Elements for High Density Resistance RAM Applications” IEDM pp. 771-774, 2007; and C. H. Ho, “A Highly Reliable Self-Aligned Graded Oxide WOx Resistance Memory: Conduction Mechanisms and Reliability” Symp. VLSI Tech., pp. 228-229, 2007; and U.S. Provisional Application 61/296,231 filed 19 Jan. 2010.
This discussed memory has a plug shape, and is associated with a relatively high current requirement when forming the memory cell.